Method and apparatus for transmitting measurement data between an object detection device and an evaluation device

ABSTRACT

An apparatus and a method for transmitting measurement data between an object-detection device and an evaluation device are provided, the evaluation device sending to the object-detection device one or more data packets with the object identifiers relevant for the evaluation device, the object-detection device inserting the current measurement data of the detected objects into a fixed, predetermined number of data packets, the objects, which the evaluation device with the aid of the object identifiers marked as relevant, being entered preferentially, and the apparatus outputting the data packet to a data bus via the connector element to the data bus.

FIELD OF THE INVENTION

An apparatus and a method for transmitting measurement data between anobject-detection device and an evaluation device are proposed; theevaluation device sending to the object-detection device one or moredata packets with the object identifiers relevant for the evaluationdevice, the object-detection device inserting the current measurementdata of the detected objects into a fixed, predetermined number of datapackets and the apparatus outputting the data packets to a data bus viathe connector element to the data bus.

BACKGROUND INFORMATION

From the publication “Adaptive Cruise Control System Aspects andDevelopments Trends” by Winner, Witte et al., released at the SAEInternational Congress and Exposition, Detroit, Feb. 26-29, 1996, anadaptive cruise controller is known which detects preceding vehicles byradar radiation and undertakes a distance control or speed control as afunction of the detected objects. It is known from this publication thatmeasurement data regarding detected objects are transmitted from a radarsystem to an ACC controller, both devices being accommodated in a commonhousing.

SUMMARY OF THE INVENTION

An object of the present invention is to exchange data between anobject-detection device and an evaluation device, the evaluation devicetransferring to the object-detection device the object identifiersrelevant for the evaluation device via one or more data packets. Ifmeasured, these identified objects are securely transmitted by theobject-detection device during the next cycle. Furthermore it is thesubject matter of the present invention that the evaluation devicespecifies for the object-detection device a distance and/or velocitywindow and that the object-detection device transmits only the measuredobject data whose objects lie within this distance and/or velocitywindow.

Advantageously, the apparatus for sensing objects, which features atleast one object-detection device as well as one connector element to adata bus, inserts the current measurement data of the detected objectsinto the data packet, the object, which the evaluation device selectedas the most relevant object, being marked. This marking advantageouslyoccurs by setting a flag, which identifies the object data of the mostrelevant object, and/or by inputting the data into the data packet in aspecified position of the data packet, for example in first position orin final position.

It is furthermore advantageous that the object-detection system includesa transmitting and receiving device for radar radiation and/or that theobject-detection system includes a transmitting and receiving device forlidar radiation and/or that the object-detection system includes areceiving device for an image processing system, for example a videocamera or a stereo video camera.

Advantageously, the data bus for transmitting the data between theobject-sensing apparatus and the apparatus for the further processing ofthe data is a CAN bus. This bus works especially reliably and can beimplemented cost-effectively.

Advantageously, the apparatus according to the present invention is usedin a motor vehicle, its use being particularly intended in a device foradaptive cruise control along the lines of a constant-distance controland a constant-speed control. The modular structure of such systems, inwhich the sensor unit and the control unit may be in separate locations,lends itself to the use of the device according to the presentinvention.

It is moreover advantageous that the marking of the measurement data ofthe object, which the evaluation device selected as the most relevantobject, is marked. This marking occurs for example by a flag and/or byinputting the object data into the data packet in a specified position.In particular, this specified position may be the first object dataposition or the final object data position.

It is furthermore advantageous that the object-detection device insertsinformation into the data packet as to whether in the previous dataexchange cycle the evaluation device already identified the particularobject as relevant or whether the object is detected for the first timeor whether it is a non-relevant object. This may occur for example bysetting a dedicated flag.

Moreover it is advantageous that the object-detection device inserts forevery detected object an object identifier, with the aid of which theevaluation device as well as the object-detection device canunequivocally identify the object.

It is especially advantageous that the data packets, which are sent bythe device featuring at least one device for further processing to thedevice featuring at least one object-detection system, contain theobject identifiers whose measurement data were sent in the previous dataexchange cycle by the device featuring the object-detection system tothe device featuring the device for further processing and which wererated as relevant by the device for further processing. The devicefeaturing the object-detection system is thereby able to ascertainwhether this object is to be rated as relevant and is thus to betransmitted preferentially during the subsequent data exchange cycle.Alternatively, this function may also be implemented in that relevantobjects are identified by the object-detection device through apreselection according to one or more criteria and are transmittedpreferentially during the subsequent data exchange cycle. Conceivablecriteria are e.g. the distance to the sensor, the transverse offsetrelative to the vehicle axis or the sensor axis and/or the frequency ofthe detections.

It is furthermore advantageous that the device for further processing ofthe measurement data specifies for the object-detection device adistance limit and/or a velocity limit or two distance limits and/orvelocity limits in the sense of a distance and/or velocity window andthat the object-detection device only takes into account the detectedobjects whose distance to the object-detection device lies below thespecified distance limit and/or whose relative velocity in relation tothe object-detection system lies below the specified velocity limit orwhose distance lies within the specified distance window and/or whosevelocity lies within the specified velocity window. The data volume canthereby be reduced in that only the most relevant objects are taken intoconsideration.

It is furthermore advantageous that the fixed, predetermined number ofdata packets provides space for measurement data of 8, 16 or 32 objects.

The realization of the method of the present invention in the form of acontrol element provided for a control unit of an adaptive distance orspeed control of a motor vehicle is of particular importance. In thiscontext, a program capable of running on a computer, in particular on amicroprocessor, and suitable only for executing the method according tothe present invention is stored on the control element. Thus, in thiscase, the present invention is implemented by a program stored on thecontrol element, so that this control element provided with the programconstitutes the present invention in the same manner as does the methodfor whose execution the program is suitable. In particular, an electricstorage medium, e.g. a read only memory, may be used as the controlelement.

Further features, uses and advantages of the present invention come tolight from the following description of exemplary embodiments of theinvention which are shown in the figures of the drawing. All thefeatures described or illustrated here, either alone or in any desiredcombination, constitute the object of the present invention, regardlessof their combination in the patent claims or their antecedent, andregardless of how they are formulated in the description or illustratedin the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a schematic representation of an apparatus according to thepresent invention.

FIG. 2 shows a flowchart representing a variant of the method accordingto the present invention.

FIG. 3 shows a flowchart representing another specific embodiment of themethod according to the present invention.

DETAILED DESCRIPTION

FIG. 1 shows the schematic representation of the apparatuses accordingto the present invention. One can see the object-sensing apparatus 1featuring at least one object-detection device 2 as well as a connectorelement to a data bus 3. Object-detection device 2 is connected via theconnector element to data bus 3, via which data may be exchanged. Shownfurthermore is a transmitting and receiving device 4 that allows theobject-detection device 2 to emit radar radiation or lidar radiationwhich is reflected at a possibly detected object 5 and is received bytransmitting and receiving device 4. In the case where object-detectiondevice 2 takes the form of an image capturing device, device 4 is a purereceiving device, since in this case an emission of transmitting signalsis not necessary. Object-detection device 2 receives the signalsreflected at objects 5 and ascertains as object measurement data atleast one of the variables: distance of the object to theobject-detection device, speed of the object relative to theobject-detection device or absolute speed of the object, acceleration ofthe object relative to the object-detection device or absoluteacceleration of the object, transverse offset of the object relative tothe central axis of the object-detection device or transverse speed ofthe object relative to the central axis of the object-detection device.The variables provided for evaluation, which include at least one of thevariables listed, are input by the object-detection device 2 into afixed, predetermined number of data packets, in which space is providedfor a predetermined number of objects with the relevant measuredvariables. These data packets are transmitted via the connector elementto a data bus 3, which may also be a gateway, via data bus 9 to aconnector element to a data bus 8, which may also be a gateway, to anapparatus for further processing 6. Apart from the connector element todata bus 8, the apparatus for further processing features at least onedevice for further processing 7. The measurement data of the receiveddata packet are fed to this device for further processing 7 and areprocessed for the respectively designated applications.

In accordance with an exemplary embodiment it is conceivable that devicefor further processing 7 sends back one or more data packets via theconnector element to data bus 8, only the object identifiers of thereceived objects being provided in the relevant data packet(s). Thisreturned packet is received by the connector element to data bus 3 andis passed on to object-detection device 2. There the object identifierssent by apparatus for further processing 6 are compared to the currentlydetected objects and are marked as relevant. The measured variables ofdetected objects 5 are written by object-detection device 2 into thedata packet, an entry being made as well as to whether the object is anewly detected object or a non-relevant object and whether it is anobject 5 selected as relevant by device for further processing 7, whichis marked separately. This marking can occur for example by setting aflag in the data packet's object variable set to be marked or by writingthe measured variables in a specially dedicated place of the datapacket, for example in the first or last position. The data packetsupdated in this manner are in turn sent via the connector elements to adata bus 3, 8, and data bus 9 to device for further processing 7, inwhich the new data are accordingly processed further.

According to a further specific embodiment, via data packets sent toobject-detection device 2, device for further processing 7 alsospecifies, in addition to the identifiers of relevant objects 5, adistance and/or velocity limit, which in the following is also referredto as a D/V window. This D/V window is defined by one or two limitdistances and/or one or two limit velocities, which are transmitted toobject-detection device 2 with the aid of data packets. Object-detectiondevice 2 subsequently filters detected objects 5 such that only thoseobjects 5 are processed further and are transmitted to device forfurther processing 7 whose distances to transmitting and receivingelement 4 are less than the distance limit specified by device forfurther processing 7 and/or whose detected velocities are below thevelocity limit specified by device for further processing 7 or whosedistances lie within the specified distance window and/or whosevelocities lie within the specified velocity window. This measure limitsthe number of detected objects 5 to the range that is of particularinterest to device for further processing 7, whereby object-detectiondevice 2 reduces the data volume to be transmitted.

FIG. 2 shows a flowchart of the method according to the presentinvention. In block 10, apparatus for further processing 6 sends toobject-sensing apparatus 1 one or more data packets containing theobjects selected as relevant by device for further processing 7. Thesedata packets are transmitted via a connector element to a data bus 8,which may also be a gateway, via a data bus 9, as well as via aconnector element to a data bus 3, which may also be a gateway. In asubsequent step, which is represented as block 11, object-detectiondevice 2 enters the measured variables of detected objects 5 into afixed, predetermined number of data packets, a note being added to therespective object data as to whether it represents a newly detectedobject or an object that is relevant for the evaluation device.Furthermore, object 5 selected by device for further processing 7 to bethe most relevant object may be marked separately, for example bymarking the relevant object measurement data with a flag or by writingthe object measurement data at a specified position into the datapacket. In the subsequent step 12, the fixed, predetermined number ofdata packets is transmitted by object-detection device 2 to device forfurther processing 7. In step 13, device for further processing 7 readsthe transmitted measurement data from the data packet and, in subsequentstep 10, sends one or more data packets containing the objectidentifiers of the objects relevant for device for further processing 7back to object-detection device 2. It is also conceivable that themethod presented is modified in such a way that the data packet is notcontinuously sent back and forth between object-sensing apparatus 1 andthe apparatus for further processing 6, but that object-detection device2 continuously generates new data packets, fills these with the measuredvariables in the manner described and subsequently sends them to devicefor further processing 7. In this case, a preselection of relevantobjects according to one or more criteria is performed in theobject-detection device. Conceivable criteria are e.g. the distance tothe sensor, transverse offset relative to the vehicle axis or the sensoraxis and/or the frequency of the detections.

FIG. 3 shows a further variant of the method described. In block 14,apparatus for further processing 6 sends one or more data packets toobject-sensing apparatus 1, these data packets containing the objectidentifiers of the objects relevant for the evaluation device as well asa D/V window, which is provided as a filter specification forobject-detection device 2. In subsequent step 15, object-detectiondevice 2 filters the detected objects according to the criteria of thespecified D/V window in that only those objects are processed furtherwhose distance to transmitting and receiving device 4 is less than thespecified distance limit value of the D/V window and/or that only thoseobjects are processed further whose measured velocity is lower than thespecified velocity limit value of the D/V window or only those objectsare processed further whose distance lies within the specified distancewindow and/or whose measured velocity lies within the specified velocitywindow. In the following step 16, object-detection device 2 writes theobject measurement data of the filtered objects into a fixed,predetermined number of data packets, thereby achieving a restriction todata relevant for the evaluation device. Furthermore, the object datawritten into the data packets are marked so as to indicate whether theyrepresent a newly detected object or an object that was marked asrelevant by the evaluation device in the previous data exchange cycle.Object-detection device 2 obtains this information by comparing theobject identifiers transmitted by device for further processing 7 to thecurrent measurement data of detected objects 5. In the subsequent step17, the data packets are transmitted from object-detection device 2 viathe connector elements to a data bus 3 and 8, and via data bus 9 todevice for further processing 7. In the following step 18, device forfurther processing 7 reads out the measurement data of the data packetsand processes them within the scope of the specified further processing.In the next step 19, one or more data packets are sent back, whichcontain the object identifiers of the objects selected as relevant bydevice for further processing 7 as well as the new distance and/orvelocity limit values, which specify the new D/V window. In thisexemplary embodiment it is also conceivable that the data packets, whichvia data bus 9 are sent back and forth between object-sensing apparatus1 and apparatus for further processing 6, are transmitted only in onedirection. To this end, object-detection device 2 in object-sensingapparatus 1 continuously generates new data packets, which are providedwith object measurement data, and sends this data packet to device forfurther processing 7. The object-detection device identifies relevantobjects on the basis of a preselection according to one or more criteriaand transmits them preferentially in the data exchange cycle. In thiscase only the new D/V window, which is defined by a distance and/orvelocity limit value, is sent in the opposite direction, that is, fromapparatus for further processing 6 to object-sensing apparatus 1.Moreover it is also conceivable that a corresponding D/V window isspecified for object-sensing apparatus 1 only once and that the distanceand/or velocity limit values are permanently stored in object-detectiondevice 2. In this case, the modification and transmission of the new D/Vwindow values from device for further processing 7 to object-detectiondevice 2 does not apply.

1. An apparatus for sensing an object and for outputting ascertainedobject data, comprising: at least one object-detection device; aconnector element for connection to a data bus; and an arrangementconfigured to send, via the connector element, a fixed, predeterminednumber of data packets provided for transmitting measurement data up toa maximum possible number of detected objects, wherein the arrangementincludes: an arrangement configured to insert current measurement dataof the detected objects into the fixed, predetermined number of datapackets; an arrangement configured to select and mark a most relevantobject; and an arrangement configured to output the data packets to thedata bus via the connector element.
 2. The apparatus as recited in claim1, wherein: the measurement data of the object selected as the mostrelevant object are marked by one of a flag and inputting object data ina predetermined data packet.
 3. The apparatus as recited in claim 1,wherein: the apparatus is at least one of a transmitting and receivingdevice for radar radiation, a transmitting and receiving device forlidar radiation, and a receiving device for an image processing system.4. The apparatus as recited in claim 1, wherein the apparatus is used ina motor vehicle in a device for adaptive cruise control along the linesof a constant-distance control and a constant-speed control.
 5. A methodfor transmitting measurement data between an object-detection device andan evaluation device, comprising: causing the evaluation device to sendat least one data packet to the object-detection device; causing theobject-detection device to insert current measurement data of a detectedobject into a fixed, predetermined number of data packets; markingobjects selected as the most relevant objects and entering the markedobjects into the fixed, predetermined number of data packets; andoutputting the data packets to a data bus via a connector element to thedata bus.
 6. The method as recited in claim 5, wherein the data packetsare provided for measurement data of a constant, predetermined number ofdetected objects.
 7. The method as recited in claim 5, wherein: themarking includes at least one of using a flag and inputting object dataat a specified position of the data packet.
 8. The method as recited inclaim 5, wherein the object-detection device inserts information intothe data packet as to whether the evaluation device already identifiedthe particular object as relevant in a preceding data exchange cycle. 9.The method as recited in claim 5, wherein the data packets containobject identifiers.
 10. The method as recited in claim 5, furthercomprising: specifying at least one of a plurality of distance limitsand a plurality of velocity limits, wherein: the object-detection deviceonly takes into account at least one of the detected objects whosedistance to the object-detection device lies within the distance limitsand the detected objects whose relative velocity in relation to theobject-detection device lies within the velocity limits.
 11. The methodas recited in claim 5, wherein the data packets are designed for aconstant, predetermined number of objects and provide measurement datafor 8, 16, or 32 objects.